A new study suggests that people are nearly twice as likely to experience mental illness in the years leading up to the onset of multiple sclerosis. According to the findings, psychiatric conditions such as anxiety and depression may be part of a prodromal phase of MS — a set of preliminary symptoms and clues that arise before classic MS symptoms.

MS is an autoimmune disorder in which the immune system attacks myelin, the protective sheath that covers nerve fibers, causing disruptions in communication to and from the brain. Recognizing MS is often challenging for medical professionals because its symptoms are varied and easily mistaken for other conditions. For many patients, this means the journey towards a diagnosis can be long and filled with uncertainty.

University of British Columbia researchers have been working to better characterize the early stages of MS with the hopes of facilitating earlier detection and possible intervention. Prodromal periods are well established in other diseases.

For the study, the researchers examined health records for 6,863 MS patients in British Columbia. They looked at the prevalence of mental health conditions, including depression, anxiety, bipolar disorder, and schizophrenia, in the five years before patients developed classical, medically recognized signs of MS. These MS patients were compared to 31,865 patients without MS.

The findings revealed that MS patients were experiencing mental illness at nearly twice the rate of the general population, at 28 percent and 14.9 percent, respectively. Healthcare usage for psychiatric symptoms — including physician and psychiatrist visits, prescriptions, and hospitalizations — was also consistently higher among MS patients. Notably, the gap widened in each of the five years leading up to disease onset.

The researchers reported seeing higher and higher rates of psychiatric conditions that peak in the final year before MS onset. While they’re not suggesting that these conditions alone can be a predictor of MS, they may be one piece of the MS prodrome puzzle and a potential signal when combined with other factors. The study builds on previous work showing that other symptoms such as fatigue, sleep disorders, irritable bowel syndrome, anemia, and pain may also be part of the MS prodrome.

The study was published in Neurology.